SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ad4834634471420fa37aa1c732d283bbcbde01699bf08793bc8c61b0e147fa' 
  AND token = 'cIaqsEq40rMqQKwSdfI7MxsKrbpisTfg6kGpQ9VkfoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}